This invention relates to apparatus and method for controlling the volume of a liquid being applied, as by spraying, on a product.
There are numerous processes wherein a liquid is applied to a product and it is desirable to adjust the volume of the applied liquid for various reasons. For example, a series of products may be moving on a conveyor or assembly line and it is necessary to spray or coat the products with a liquid. The volume of the liquid may be adjusted in accordance with the quantity or weight of the product to be sprayed, for example, or the volume may be adjusted to change the ratio of the amount of liquid to the unit volume of the product. In the specific example described herein, a liquid oil is sprayed on grain for dust suppression purposes while the grain is moving in a conveyor.
In such a system it is also important that the spray pattern be consistently good so that the product or products will be evenly covered. The volume of the liquid could be adjusted by changing the pressure of the liquid flowing through a spray nozzle, but a change in the pressure may also produce an undesired change in the spray pattern. Further, there may be an optimum pressure for a good pattern from a spray nozzle, and, any pressure adjustment to change the volume might also decrease the quality of the spray pattern.
It is a general object of the present invention to provide a spray volume control system which avoids the foregoing problems.